The present invention relates generally to lock devices and, more particularly, to a lock assembly with a key-activated removable core structure.
A cylinder lock comprises a central plug or core and an outer shell or housing, in which the core rotates. The housing is mounted in a suitable latch structure. A number of prior art disclosures describe devices intended to provide a removable core in a cylinder lock. The advantage of removable core locks is that they may be rapidly re-keyed by relatively unskilled personnel. Such re-keying may be required as a result of a potential security breach or occurring due to the loss or non-return of a key.
The patent publication U.S. Pat. No. 5,070,715 (Smallegan et.al.) describes a removable core lock wherein a locking pin is arranged to engage a recess in the lock housing. The locking pin is actuated by means of a dedicated key operated control pin engaging an actuating ring and deactivating a locking pin stop latch.
While this solution provides for a reliable removable core, it is accompanied by several drawbacks. Firstly, a dedicated locking pin is used which cannot be used for coding of the lock and which contributes to the volume occupied by the core. Secondly, the control key used for operating the control pin is longer than user keys, necessitating key blanks of different lengths. Thirdly, the blocking arrangement comprises many parts, contributing to the cost of the lock. Lastly, the control pin can be manipulated by a fraudulent person trying to remove the core.
An object of the present invention is to provide a removable core lock wherein the drawbacks of prior art devices are eliminated or at least mitigated.
The invention is based on the realization that one of the pin tumblers used for blocking the rotation of the key plug can be used to control an actuator element controlling a locking element preventing or allowing removal of the cylinder core.
According to the invention there is provided a removable core lock and key device as defined in claim 1.
With the inventive device the above-mentioned drawbacks of prior art are eliminated or at least mitigated. The lock device according to the present invention as defined by the appended claims has a configuration wherein a simple design involving an actuator element and a blocking element provides the removable core function.
In a particularly preferred embodiment, an actuator element comprises an actuator ring arranged around the plug, wherein the ring has a hole for at least one control pin tumbler.
Further preferred features are defined in the dependent claims.